1. Field of the Invention
The present invention relates to a method for 1:1 format size or for the geometric calibrating of a feed through scanner or transport scanner that is arranged for scanning a two-dimensional original and forming an electronic image for subsequent usage in an appropriate information handling system. The scanning and forming steps are executed under the control of device parameters and the method includes the steps of scanning a test original, provided with a test image and then forming an electronic image. The invention also relates to an apparatus having a transport scanner facility and a test original for use with the present method.
2. Related Art
Transport or feed through scanners are being used for deriving a complete and conforming image from an original, either for the purpose of immediate copying thereof, or for intermediate storage with an intention to later usage of the information for manipulation and/or eventual delayed copying or printing. In particular, but not by way of limitation, the original may have an appreciable size such as an A0 or A1 format, and may even stretch out in one direction, such as in the form of a semi-infinite roll. On the other hand, the original may also have quite a smaller size. The content of the image is inconsequential, but various applications may range from cartography to mechanical engineering. Such transport scanner distinguishes from a so-called flat-bed scanner in that in the former the original moves along a fixed optical arrangement of the apparatus that usually is realized as an array of CCD elements which runs generally transverse to the direction of motion of the original.
Now, various geometrical uncertainties will exist in the apparatus as recited, where against both the size and the timing of the array of CCD elements would need calibration. Furthermore, also the transport mechanism and the precise location of the original in a transverse direction to the transport vector would justify effort for precise calibration. All these calibrations are relative to the standard size original that would effectively be used. The problem is aggravated in that the transport mechanism and the geometrical scaling of the image by the optical arrangement are governed by quite different control mechanisms. Particular problems are caused by uncertainties in the leading edge position and trailing edge position of the original and in the transport speed vis-à-vis the optical arrangement.
Current practice with such transport scanners has been to provide such standard size original, to make a copy thereof, and to have any necessary calibrations applied to the scanner facility by a skilled technician. The ongoing advance of technology and its rising degree of sophistication, and furthermore the increasing usage of such transport scanners have made the necessity for such manual calibration an appreciable burden, both in terms of cost and in terms of delays incurred, in particular when the scanner may be subject to temporal drifting.
Moreover, according to prior practice, generally an already adjusted printer must be present in the overall system, which may necessitate taking recourse to a remote facility. A further problem will be met when the scanner is not locally connected to an actual printer or copier facility, which may then be present instead in a remote location, or be only available after an appreciable delay.